Abstract: Nano-sized bone products were made from fish bone, pig bone, bovine bone and chicken bone using highenergy wet milling, respectively. Their properties were investigated in order to provide a theoretical foundation for the production and application of nano-sized bone products. The proximate compositions of bones of four different animals were significantly different (P < 0.05). Briefly, ash content was the highest in fish bone while crude fat and protein were the highest in chicken bone. After high temperature treatment (120 ℃), the wavenumbers and intensities of the characteristic absorption bands assigned to phosphate group (PO4 3-) did not significantly change. However, the protein absorption bands at 1 450?1 700 cm-1 were obviously different between fish bone and the others. Average particle size of fish bone was reduced to nanometer range (162 nm) after 1 h milling, and was 135 nm after 2 h milling, while average particle sizes of pig bone, bovine bone and chicken bone were below 200 nm after 2, 2 and 5 h milling, respectively. The minimum average particle size for fish bone, pig bone, bovine bone and chicken bone were 117, 105, 89 and 153 nm, respectively. During the milling process, the release rate of calcium linearly increased, pH increased and then kept steady, lightness and whiteness significantly increased, free amino acid and trichloroacetic acid-soluble peptide contents dramatically increased. Therefore, fish bone may be the most suitable material for producing nano-sized bone product with improved breakage efficiency and whiteness.

Key words: bone, wet milling, nanosized particle, physicochemical properties